Ningetinib, a novel FLT3 inhibitor, overcomes secondary drug resistance in acute myeloid leukemia.

BACKGROUND: FMS-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) is a common mutation type in acute myeloid leukemia (AML) and is usually associated with poor patient prognosis. With advancements in molecular diagnostics and the development of tyrosine kinase inhibitors (TKI), the overall survival (OS) of AML patients with FLT3-ITD mutations has been prolonged to some extent, but relapse and drug resistance are still substantial challenges. Ningetinib is a novel TKI against various kinases in relation to tumour pathogenesis and is undergoing clinical trials of lung cancer. In this study, we explored the antitumor activity of ningetinib against AML with FLT3 mutations both in vivo and in vitro. METHODS: Cell proliferation assays were performed in AML cell lines and Ba/F3 cells expressing various FLT3 mutations to validate the antileukemic activity of ningetinib in vitro. Immunoblot assays were used to verify the effect of ningetinib on the FLT3 protein and downstream pathways. Molecular docking and CETSA were used to validate the interaction of ningetinib with target proteins. The survival benefit of ningetinib in vivo was assessed in Ba/F3-FLT3-ITD-, MOLM13, Ba/F3-FLT3-ITD-F691L-, MOLM13-FLT3-ITD-F691L-induced leukemia mouse models. We also used patient-derived primary cells to determine the efficacy of ningetinib. RESULTS: Ningetinib inhibited cell proliferation, blocked the cell cycle, induced apoptosis and bound FLT3 to inhibit its downstream signaling pathways, including the STAT5, AKT and ERK pathways, in FLT3-ITD AML cell lines. In the mouse models with FLT3-ITD and FLT3-ITD-F691L mutation, ningetinib showed superior anti-leukemia activity to existing clinical drugs gilteritinib and quizartinib, significantly prolongating the survival of mice. In addition, ningetinib exhibited activity against patient-derived primary cells harboring FLT3-ITD mutations. CONCLUSION: Overall, our study confirmed the therapeutic role of ningetinib in AML with FLT3-ITD mutations, providing a potential new option for clinically resistant patients.

Increased co-expression of ICOS and PD-1 predicts poor overall survival in patients with acute myeloid leukemia.

BACKGROUND: Inducible co-stimulatory factor (ICOS) has a dual role: activating cytotoxic T cells against tumors or exacerbating immunosuppression of regulatory T cells (Tregs) to participate in immune evasion. However, the correlation between ICOS and its co-expression with inhibitory immune checkpoints (IICs) and prognosis in acute myeloid leukemia (AML) is little known. METHODS: The prognostic importance of ICOS and IICs in 62 bone marrow (BM) samples of de novo AML patients from our clinical center (GZFPH) was explored and then the RNA sequencing data of 155 AML patients from the Cancer Genome Atlas (TCGA) database was used for validation. RESULTS: In both GZFPH and TCGA cohorts, high expression of ICOS was significantly associated with poor overall survival (OS) in patients with AML (P < 0.05). Importantly, co-expression of ICOS and PD-1, PD-L1, PD-L2, CTLA-4, and LAG-3 predicted poor OS in AML; among them, ICOS/PD-1 was the optimal combination of immune checkpoints (ICs). The co-expression of ICOS and PD-1 was correlated with poor OS in non-acute promyelocytic leukemia (non-APL) patients following chemotherapy. Additionally, ICOS/PD-1 was an independent OS-predicting factor (P < 0.05). Notably, a nomogram model was constructed by combining ICOS/PD-1, age, European Leukemia Net (ELN) risk stratification, and therapy to visually and personalized predict the 1-, 3-, and 5-year OS of patients with non-APL. CONCLUSION: Increased expression of ICOS predicted poor outcomes, and ICOS/PD-1 was the optimal combination of ICs to predict outcomes in patients with AML, which might be a potential immune biomarker for designing novel AML therapy.

Foretinib Is Effective in Acute Myeloid Leukemia by Inhibiting FLT3 and Overcoming Secondary Mutations That Drive Resistance to Quizartinib and Gilteritinib.

FLT3 internal tandem duplication (FLT3-ITD) mutations are one of the most prevalent somatic alterations associated with poor prognosis in patients with acute myeloid leukemia (AML). The clinically approved FLT3 kinase inhibitors gilteritinib and quizartinib improve the survival of patients with AML with FLT3-ITD mutations, but their long-term efficacy is limited by acquisition of secondary drug-resistant mutations. In this study, we conducted virtual screening of a library of 60,411 small molecules and identified foretinib as a potent FLT3 inhibitor. An integrated analysis of the BeatAML database showed that foretinib had a lower IC50 value than other existing FLT3 inhibitors in patients with FLT3-ITD AML. Foretinib directly bound to FLT3 and effectively inhibited FLT3 signaling. Foretinib potently inhibited proliferation and promoted apoptosis in human AML cell lines and primary AML cells with FLT3-ITD mutations. Foretinib also significantly extended the survival of mice bearing cell-derived and patient-derived FLT3-ITD xenografts, exhibiting stronger efficacy than clinically approved FLT3 inhibitors in treating FLT3-ITD AML. Moreover, foretinib showed potent activity against secondary mutations of FLT3-ITD that confer resistance to quizartinib and gilteritinib. These findings support the potential of foretinib for treating patients with AML with FLT3-ITD mutations, especially for those carrying secondary mutations after treatment failure with other FLT3 inhibitors. SIGNIFICANCE: Foretinib exhibits superior efficacy to approved drugs in AML with FLT3-ITD mutations and retains activity in AML with secondary FLT3 mutations that mediate resistance to clinical FLT3 inhibitors.

Letermovir Effectively Prevents Cytomegalovirus Infection in Patients with Aplastic Anemia After Hematopoietic Stem Cell Transplantation: A Real-World Retrospective Cohort Study.

INTRODUCTION: In this single-center retrospective cohort study, we investigated the efficacy of letermovir in preventing Cytomegalovirus (CMV) infection in patients with aplastic anemia (AA) who have undergone allogeneic hematopoietic stem cell transplantation (allo-HSCT). METHODS: Based on whether or not letermovir was used for preventing CMV infection, the patients were categorized into two groups: letermovir and control groups. The overall survival (OS) rate and cumulative incidence of CMV infection during the first 100 days after allo-HSCT were evaluated. The study included 21 matched pairs of patients, identified through propensity score matching analysis, to compare CMV infection rates, treatment efficacy, and regression. RESULTS: The incidence of CMV infection within 100 days after transplantation was significantly lower in the letermovir group than in the control group (26.5 vs. 77.4%, respectively; P < 0.001), among a total of 87 patients who underwent the transplant. In the matched cohort of 21 patients with AA, the letermovir group also showed a significantly reduced cumulative incidence of CMV infection (14.3 vs. 90.5% in the control group; P < 0.001). Compared to the control group, patients with CMV infection in the letermovir group had lower CMV-DNA load and a shorter clearance time. However, there was no significant difference in OS between both groups (P = 0.34). CONCLUSIONS: Letermovir effectively prevents CMV infection in allo-HSCT recipients with AA and demonstrates a high safety profile.

Optimal combination of immune checkpoint and senescence molecule predicts adverse outcomes in patients with acute myeloid leukemia.

BACKGROUND: High expression of immune checkpoints (ICs) and senescence molecules (SMs) contributes to T cell dysfunction, tumor escape, and progression, but systematic evaluation of them in co-expression patterns and prognosis in acute myeloid leukemia (AML) was lacking. METHODS: Three publicly available datasets (TCGA, Beat-AML, and GSE71014) were first used to explore the effect of IC and SM combinations on prognosis and the immune microenvironment in AML, and bone marrow samples from 68 AML patients from our clinical center (GZFPH) was further used to validate the findings. RESULTS: High expression of CD276, Bcl2-associated athanogene 3 (BAG3), and SRC was associated with poor overall survival (OS) of AML patients. CD276/BAG3/SRC combination, standard European Leukemia Net (ELN) risk stratification, age, and French-American-British (FAB) subtype were used to construct a nomogram model. Interestingly, the new risk stratification derived from the nomogram was better than the standard ELN risk stratification in predicting the prognosis for AML. A weighted combination of CD276 and BAG3/SRC positively corrected with TP53 mutation, p53 pathway, CD8+ T cells, activated memory CD4+ T cells, T-cell senescence score, and Tumor Immune Dysfunction and Exclusion (TIDE) score estimated by T-cell dysfunction. CONCLUSION: High expression of ICs and SMs was associated with poor OS of AML patients. The co-expression patterns of CD276 and BAG3/SRC might be potential biomarkers for risk stratification and designing combinational immuno-targeted therapy in AML.Key MessagesHigh expression of CD276, BAG3, and SRC was associated with poor overall survival of AML patients.The co-expression patterns of CD276 and BAG3/SRC might be potential biomarkers for risk stratification and designing combinational immuno-targeted therapy in AML.

Prospective Study of a Modified Post-Transplantation Cyclophosphamide Regimen for Severe Aplastic Anemia Patients with HLA-Haploidentical Transplantation.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative modality for severe aplastic anemia (SAA). The availability of haploidentical donors has expanded valid options for SAA; however, previous post-transplantation cyclophosphamide (PTCy)-based protocols for HLA-haploidentical HSCT in SAA patients are associated with relatively delayed neutrophil and platelet engraftment. We prospectively studied HLA-haploidentical HSCT using bone marrow (BM) combined with peripheral blood stem cells (PBSC) as grafts and a modified PTCy regimen for treating SAA. We evaluated the efficacy and safety of this regimen, which had an increased dose (from 4.5 mg/kg to 6.0 mg/kg) and backward-adjusted timing (from day -9 to -7 to days -5 to -3) of antithymocyte globulin (ATG) compared with previous PTCy protocols. Seventy-one eligible patients were included in this prospective study between July 2019 and June 2022. The median time to neutrophil and platelet engraftment was 13 days (range, 11 to 19 days) and 12 days (range, 7 to 62 days), respectively, and the cumulative incidence (CuI) of neutrophil and platelet engraftment was 97.2 ± 2.2% and 94.4 ± 2.9%, respectively. Five patients experienced graft failure (GF), including 2 with primary GF and 3 with secondary GF. The CuI of GF was 7.0 ± 3.1%. A ≥1-year interval between diagnosis and transplantation was a risk factor for the development of GF (HR, 8.40; 95% confidence interval [CI], 1.40 to 50.47; P = .02). No patients developed grade IV acute graft-versus-host disease (aGVHD) or severe chronic graft-versus-host disease (cGVHD). The 100-day CuI of grade II-IV aGVHD was 13.4 ± 4.2%, and the 2-year CuI of cGVHD was 5.9 ± 2.9%. With a median follow-up of 580 days (range, 108 to 1014 days) for 63 survivors, the estimated 2-year overall survival (OS) and 2-year GVHD-free and failure-free survival (GFFS) were 87.3% (95% CI, 79.4% to 96.0%) and 83.8% (95% CI, 74.9% to 93.7%), respectively. In conclusion, the PTCy regimen with an increased dose and backward-adjusted timing of ATG is an effective and feasible choice for treatment with HLA-haploidentical HSCT using BM combined with PBSC as grafts, with a high rate of and faster engraftment, low rate and intensity of aGVHD and cGVHD, and prolonged OS and GFFS.

LncRNA USP30-AS1 promotes the survival of acute myeloid leukemia cells by cis-regulating USP30 and ANKRD13A.

Acute myeloid leukemia (AML) is a malignant tumor derived from leukemia stem cells, with complicated pathogenesis. LncRNAs play an important role in tumors genesis and progression. According to results from bioinformatics analysis, lncRNA USP30-AS1 is highly expressed in AML and both the high expression of USP30-AS1 and low methylation level at Cg03124318 locus of USP30-AS1 gene promoter are associated with poor prognosis of AML. This study knocked down and overexpressed USP30-AS1 to determine the roles in AML cell lines. High-throughput sequencing was performed to explore the genes regulated by USP30-AS1. Results showed that USP30-AS1 promoted AML cell viability and inhibited apoptosis. Genes regulated by USP30-AS1 are mainly related to genetic regulation and immune system. Among them, USP30 and ANKRD13A genes are close to USP30-AS1 gene in chromosome. Knockdown of USP30, but not ANKRD13A, abolished the cancer-promoting effects of USP30-AS1. ANKRD13A recognizes Lys-63-linked polyubiquitin chain in HLA-I. USP30-AS1 induced HLA-I internalization from the cell membrane by up-regulating ANKRD13A, which might induce the immune escape of AML cells. ChIP analysis revealed that the regulatory effects of USP30-AS1 on USP30 and ANKRD13A are associated with H3K4me3 and H3K27Ac. In summary, USP30-AS1 probably promotes AML cell survival by cis-regulating USP30 and ANKRD13A.

Outcome of allogeneic hematopoietic stem cell transplantation for hypoplastic myelodysplastic syndrome.

The prognosis of patients with hypoplastic myelodysplastic syndrome (hMDS) after receiving allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains unclear. This study aimed to evaluate the outcomes of patients with hMDS after allo-HSCT. Between September 2013 and October 2019, a total of 20 consecutive patients with hMDS and 1 patient with clonal cytopenia of undermined significance (CCUS) who underwent allo-HSCT, which included procedures with 9 matched sibling donors, 2 matched unrelated donors, 4 mismatched unrelated donors and 6 haploidentical donors, were enrolled in this study. The median time for myeloid engraftment was 11 days (range 9-17 days), and that for platelet engraftment was 10 days (range 7-17 days). The cumulative incidence (CI) of myeloid and platelet recovery was 95.2 ± 6.0% and 90.5 ± 7.3%, respectively. The CI rates were 40.0 ± 11.3% for grades II-III acute graft-versus-host disease (GVHD), 36.8 ± 11.5% for chronic GVHD and 23.8 ± 9.6% for nonrelapse mortality. No patients experienced relapse. Sixteen surviving patients were followed up for a median of 1113 days (range 110-2305 days), and the overall survival and relapse-free survival rates were both 72.7 ± 10.6%. This limited retrospective analysis suggests that patients with hMDS had a favorable survival after allo-HSCT.

Expression profile analysis of prognostic long non-coding RNA in adult acute myeloid leukemia by weighted gene co-expression network analysis (WGCNA).

Background: Long non-coding RNAs (lncRNAs), which are over 200 nt in length, have a key role in tumorigenesis and disease progression. To explore the role of prognostic lncRNAs in adult acute myeloid leukemia (AML), the expression profiles of lncRNAs and mRNAs in AML were analyzed. Methods: The RNAseq data of 167 adult AML patients and the corresponding clinical information were downloaded from The Cancer Genome Atlas (TCGA), which is a publicly available database. The RPKM values of the RNAseq data were subjected to weighted gene co-expression network analysis (WGCNA) in modularization. Results: We identified survival specific lncRNAs and mRNAs, which were divided into modules by coexpression analysis. The lncRNAs were mainly annotated into "Fc gamma R-mediated phagocytosis". The hub lncRNA and co-expressed mRNAs were further selected for analysis of risk stratification. LncRNA-LOC646762 may contribute to AML through the "endocytosis" signaling pathway. Finally, the expression levels of LOC646762 and co-expressed CCND3, CBR1, C10orf54, CD97 and BLOC1S1 in the adult AML patients and healthy volunteers were validated by qRT-PCR, and then their roles in prognosis and risk stratification were identified. Conclusions: Prognostic lncRNA-LOC646762, which may contribute to AML through the "endocytosis" signaling pathway, may act as a biomarker for predicting the survival of adult AML patients, as well as for risk stratification.

lncRNA-CCDC26, as a novel biomarker, predicts prognosis in acute myeloid leukemia.

The aim of the present study was to examine the expression and clinical significance of long non-coding RNA (lncRNA)-CCDC26 in patients with acute myeloid leukemia (AML), and to investigate the potential functions of CCDC26. The Gene Expression Omnibus database and reverse transcription-quantitative polymerase chain reaction analysis were used to detect the expression levels of CCDC26 in patients with AML and healthy volunteers. Clinical data for 93 patients with AML were collected to analyze the clinical significance of CCDC26. Weighted gene co-expression network analysis (WGCNA), a protein-protein interaction (PPI) network, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were used to examine the functions of CCDC26. The expression levels of CCDC26 in the initially diagnosed and relapsed patients with AML were significantly upregulated compared with the control group. The upregulated expression level of CCDC26 in patients with AML was significantly associated with age, anemia, risk stratification and remission. Furthermore, patients with a high CCDC26 expression level had a poorer overall survival (P=0.0105). In addition, the area under the curve (AUC)1year and AUC2year of CCDC26 for overall survival were 0.722 and 0.686, respectively. WGCNA, PPI network and KEGG pathway analysis revealed that CCDC26 was involved in the regulation of a number of biological processes. lncRNA-CCDC26 may serve as a novel biomarker for monitoring the progression and predicting the clinical outcome of AML.

[Large scale expansion of hematopoietic progenitor cells from umbilical cord blood by magnet stirred culture system].

The aim of this study was to expand hematopoietic progenitor cells at large scale by magnet stirred culture system. Mononuclear cell from umbilical cord blood were cultured in serum-free medium with stem cell factor, FIT-3 ligand and thrombopoietin. Firstly, the role of magnet on cell growth and colony-forming was studied by static culture on 0, 25 and 50 mT. Then the expansion multiple of cells, colony-forming and expression of surface markers were studied in magnet stirred culture by cell counting, colony-forming assay and flow cytometry. The results indicated that there was no difference in multiple of total cell expansion and numbers of hematopoietic colonies between 0, 25 and 50 mT groups and spinner groups (all p > 0.05). After 7 day cultures, the multiple of total cell expansion in magnet stirred culture was higher than that in static culture (p < 0.01). The numbers of CFU-GM (colony-forming unit-granulocyte/macrophage) and CFU-E (erythroid colony forming unit) in magnet stirred culture were higher than those in static culture, (p < 0.05). The primitive cells (CD34(+), CD34(+)/CD38(-) or CD133(+)) of the expanded cells in magnet stirred culture were less than those in static culture (p < 0.05). However, the CD184(+) or CD62L(+) expanded cells were more than that in static culture (p < 0.05). It is concluded that magnet stirred culture favors the expansion of hematopoietic progenitor cells. The results will be finally confirmed in further in vivo experiments and clinical applications.